PyGRP: Display the name of the opened file in the window's title bar. It'd be nice when browsing through multiple GRPs and you forget which one you just opened.

PyGRP: Background color selection option. That way, you can view a GRP with more than just a black background, which might obscure rogue pixels. A field for a hex color and a couple preset color boxes would suffice.

PyGRP: Textured background display option. Presets could be some of StarCraft's tilesets, so you can get an idea of what a GRP would look like over terrain. Maybe also have an address field for a custom background texture.

The window is a bit small to fit most file paths, but i guess I could only display the file name.

You can select the background color by double clicking the preview window. I actually thought of allowing you to choose an image as a background so you could test on terrain, but I never implemented it. Thanks for the ideas!